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Tuesday, October 18, 2016

In late February of this year, MOH and I were intent on getting down the Titus Canyon road to see the superbloom in Death Valley, which was going great guns down near Badwater. We nevertheless stopped for a hike not far downstream from the photo in my last post.

A few wildflowers bloom in front of an orange-brown outcrop of Carrara Formation limestone.

Before hiking some really steep cliffs on the north canyon wall, I looked to the south to grab a few geological photos, not realizing that besides the nice example of dipping beds, I was seeing a good example of one splay of the Titus Canyon fault zone (TCFZ).

Beds on the south wall of the canyon are dipping in a northerly direction.

In the labeled view below, we see the approximate line of one splay of the TCFZ. It has crossed the wash left of the photo (and in front of us in last week’s photo); it goes up, over, and back behind the foreground rocks (the arrow pointing the way); and it eventually wraps around to hook up with the low-angle fault on the more distant, shadowed hill. This interpretation of the location of a main splay of the TCFZ is from Reynolds, as seen in Lengner and Troxel (2008), and is also an extrapolation from Niemi’s 2012 map.

A splay of the younger-on-older TCFZ can be seen here in hachured dark blue. It is placing the younger Bonanza King Formation (Єb) above the older Carrara Formation (Єc) and even older Zabriskie Quartzite (Єz).

Disclaimers: My placement of the fault is approximate, the foreground part of the fault might be modified by a high-angle normal fault, and the cliff and hills labeled Єz may include some faulted-in Єc.

I’ve zoomed in here, just so we can see the fault exposure a little better.

The rocks above the nicely bedded section on the right (Єc) look chaotically fractured and possibly brecciated. I read somewhere that the Fe-oxide staining of the rocks is typical of the damage zone along the fault. This unpublished map has a mélange unit devoted to certain parts of the TCFZ damage zone. That unit (TfxT; description here) is reported to be particularly pronounced along the westernmost portion of the TCFZ.

MOH and I had stopped at this particular point in order to go on a smallish hike—well, we actually stopped to investigate a dry waterfall, and that investigation turned into a scramble (probably Class 3).

We’re looking up a side drainage on the steep north side of Titus Canyon. The overexposed white areas are limestone that has been scoured and polished by running water and entrained debris.

It turns out that this is a decent location to view the Titus Canyon fault.

The Titus Canyon fault places the Bonanza King (Єb) over the Carrara (Єc). It is mostly (or entirely) behind the lower cliffs on the right side of the photo.

And now, for a little map comparison, before we scramble up the slickrock.

A similar bit of Google Earth (GE), uncorrected for any possible skewness in orientation. The TCFZ is in magenta; other normal faults are in blue and dark blue; the Zabriskie Quartzite (Єz) is outlined in red

My interpretation of the location of the TCFZ north of the canyon is based largely on a single photo in Lengner and Troxel (2008; their Figure 6.17, p. 114).

How do these maps line up?

I’ve managed to overlay a transparent version of Niemi’s map on top of the Google Earth image.

I’ve corrected a bit of Niemi’s map where I think the labeling and coloring of a portion of Bonanza King Formation (his Єpb, my Єb) and Titus Canyon Formation (EOgtc) was accidentally switched. The overlay is not perfect: The programs I used (Word and Paint) are really not designed for precision. Nevertheless, we see some correlation between the two maps. Interestingly, the place where the two maps show the most divergence is right where Lengner and Troxel have their photo (where my magenta line does a lot of contortions). As far as ground checking of this TCFZ-modified Єb-Єc contact, it’s difficult to impossible to walk up to the fault in most places—at least not without using real climbing techniques or hanging oneself out of a helicopter on a rope!

Now we’ll get on with our hike!

A small pool of water at the base of the lower chute.

We've now walked over to the base of the waterfall, where...we find some water!

For scale, I offer a fly on the far right.

The fly is sunning itself on polished Carrara Formation, which consists here of blue-gray limestone with orange claystone partings and wavy bedding.

I’ve now scrambled up to a ledge and am looking up the Carrara cliff to the jagged outcrops of Bonanza King Formation (Єb) beyond.

The faults drawn in are mostly hidden from view by the jutting lower cliff of Carrara Formation (Єc). The TCFZ, in hachured dark blue, is offset by a high-angle normal fault in lighter blue.

I love barrel cacti!

I’ve now scrambled even higher, to stand below a second polished chute.

The third polished chute, even higher, is above a large, dry plunge pool.

This is as high as I got on this dry falls. MOH went up higher, probably to the TCFZ. I didn’t know there was a fault up there, or I might have been tempted to try to climb higher, even though I was about at the edge of my free-climbing competence. I scrambled back down and eventually found myself overlooking the first waterhole.

I stand on a ledge above the first pothole.

Right after taking this photo, I was maneuvering across a jutting portion of tear-a-pants limestone when I lost all but one point of contact and tumbled down toward the overhang above the pothole. I managed to recover on a smallish ledge. I was okay, but it really was close. That’s probably the last bit of free-climbing I’ll do! The DSLR fell also, hitting the rock I landed on, and somehow, it was also okay! (I was surprised. Possibly this is a testimony to Nikon.)

Our next stop will be a little farther downstream, closer to Klare Spring.